This invention relates generally to article transfer systems, and more particularly, to a system having a transfer head with a plurality of article holders which may be advantageously configured to conform to a selectable one of alternative array arrangements.
It is often desirable in production systems to move a group of spaced articles from one location to another. Such articles may include eggs, which are desired to be moved as a group. For example, eggs are generally provided on transport flat trays which are configured with recesses wherein the eggs are placed in an array arrangement. The egg trays may be delivered by a conveyor or other transport means to a location at which it is desired to remove the eggs from the flat trays as a group so that the group may be transported to another location, which may be a further conveyor system, illustratively for washing or the like.
The transport mechanism may be comprised of a transfer head which contains a plurality of known vacuum cups which are arranged in the transfer head so as to conform to the array arrangement of the eggs in the transport trays. Once a tray has been placed and aligned under the transfer head, the transfer head will descend over the eggs until the vacuum cups engage with respectively associated eggs. Once the eggs have been engaged by the transfer head by means of the vacuum cups, the head and eggs may be lifted and moved, illustratively by a mechanical lifting arm, to a further location where it is desired to deposit the eggs for further processing.
In certain known egg transfer systems, egg trays are removed from alternatingly rotated stacks, loaded onto a conveyor system for processing, and restacked. Every second one of the egg trays is rotated by 90.degree. as they are lifted from the original stack and loaded into the conveyor. After processing, the egg trays are lifted from the conveyor, every second one being rotated by 90.degree. so as to restack the egg trays in the alternatingly rotated configuration. It is a problem with the known systems of this type that, during the rapid operation of the machine, the egg trays are rotated very quickly. Thus, such a rotative system cannot be used at high production rates in arrangements where the individual eggs are lifted from a tray as a group by respectively associated vacuum cups, because the centrifugal force created by the rapid rotation causes some of the eggs to be released. In addition, such head rotation creates design problems as a result of the space required to achieve rotation.
Although the prior art has provided systems for adjusting the inter-article spacing of the articles in a transfer head or at the location of deposition, the known systems have not solved the problems associated with picking up a plurality of articles which are arranged in a first array configuration, and depositing them at a further location, or at the same location, in a second array arrangement, in a simple and effective manner. For example, in the case of egg transfer systems which utilize vacuum cups, eggs are collected at a collection location, in an array arrangement having illustratively 6 rows by 5 columns. It may subsequently be desired to deposit the eggs at a deposition location in an array arrangement having 5 rows by 6 columns. In some article transfer systems which are limited in space, it is neither feasible nor desirable to rotate the transfer head 90.degree. to achieve the new array configuration. Such rotation of the transfer head, as noted above, creates mechanical design problems as a result of; the complex mechanisms which are required for transmitting rotational motion to the transfer head; the control of such motion to achieve the desired alignment accuracy; and the need for a strong vacuum supply for holding the eggs in the vacuum cups if the transfer head is to be rotated quickly and stopped in a short time.
It is, therefore, an object of this invention to provide a simple and inexpensive transfer head arrangement which can convert a first article array arrangement into a second array arrangement.